Diff: Sampling.h

Revision:

19:40c721f01ed2

Parent:

12:03589f1d5c30

Child:

21:6e733076f49c

--- a/Sampling.h	Tue Jan 09 10:25:17 2018 +0000
+++ b/Sampling.h	Tue Jan 09 11:39:59 2018 +0000
@@ -1,6 +1,23 @@
 #ifndef __Sampling__
 #define __Sampling__
-
+/*
+* This module relates to the handling and sampling of enviromental data.
+* Sampled data is held in 4 arrays. One for each different reading. Each
+* of these is protected by a mutex lock, which is taken when data is being
+* written to the registers.
+* There are common indexes for the positions in the array. Stored is the position
+* position of the oldest sample, the most recent sample, and where the next
+* sample is to be written to. These operate in such a way that the array will fill
+* and when fill will start to overwrite the oldest sample.
+* Producer functions write samples to nextIndex position, allowing the most
+* recent complete sample to continue to be read by consumers.
+* 
+* A ticker runs at the sample rate interval. This signals two sampling threads.
+* Two threads were used to prevent against delay from I2C interface.
+* These threads take the samples then write them to the nextIndex, then signal done.
+* On seeing that both threads are complete, the main thread then increments the
+* indexes and passes the latest variables to the LCD.
+*/
 #include "mbed.h"
 #include "BMP280.h"
 #include "rtos.h"